Carton sealing apparatus



Nov. 28, 1961 R. R. RICHARDSON ET AL CARTON SEALING APPARATUS 2sheets-sheet 1 Filed May 25, 1959 Nov. 28, 1961 R. R. RICHARDSON ET AL3,010,267

CARTON SEALING APPARATUS 2 Sheets-Sheet 2 Filed May 25 1959 M1: ha( 5.

5 f m w United States Patent Ofce 3,l0,267 Patented Nov. 28, 19613,010,267 CARTON SEALING APPARATUS Ralph R. Richardson and John M.Langland, Chicago,

Ill., assignors, by mesne assignments, to Chicago Carton Company,Chicago, Ill., a corporation of Dela- Ware Filed May 25, 1959, Ser. No.815,479 3 Claims. (Cl. 53-379) The present invention relates generallyto an apparatus for sealing cartons, and more particularly to anapparatus for heat sealing cartons containing thermoplastic substances.

Cartons are ordinarily sealed either with solvent dispersed adhesives orwith thermoplastic sealing compounds. However, in Vthe case of cartonscontaining thermoplastic substances, such as margarine, butter, etc., ithas previously been considered impractical to heat seal the cartons, forif the heat ytransferred to the cartons to melt the thermoplasticcompound was excessive, it would result in undesirable melting of thethermoplastic within the cartons. This was especially true in the caseof an interruption of the movement of the cartons past the heatingdevices. l

Therefore, in previously available packaging machines for thermoplasticsubstances, the cartons have been sealed by applying a solvent dispersedadhesive, such as paste, to the closure aps. It has been found that theseal provided by utilizing paste has been easily opened and, in fact,has oftentimes come open during shipment. Moreover, such a seal has beenineffective to prevent tampering with the contents within the cartons.

Maintenance has always been a problem with pastesealing equipment. Sincedirt and cardboard waste readily stick to the paste, such equipmentrequires frequent cleaning. Also, the paste applicator becomes easilycloggedwith dried paste or such, necessitating a shut down of thepackaging operation.

Accordingly, an object of the present invention is the provision of anapparatus for heat sealing cartons containing thermoplasic substances,such as butter and margarine. Another object is the provision of anapparatus for heat sealing cartons issuing from a margarine packingmachine without melting the margarine with the cartons. A further objectis the provision of an apparatus adapted for heat sealing cartonscontaining thermoplastic substances which apparatus is provided with ameans for rapidly reducing the heat applied to the cartons in case of aninterruption of the movement of the cartons through the apparatus. Stilla further object is the provision of a heat sealing apparatus forcartons containing thermoplastic substances which is eliicient inoperation and requires little or no maintenance.

Other objects and advantages of the present invention will becomeapparent by reference to the following description and accompanyingdrawings.

In the drawings:

FIGURE 1 is a side elevational View of a carton sealing apparatusembodying various features of the present invention, with portions ofthe apparatus being broken away to show the internal constructionthereof;

FIGURE 2 is a plan view of the carton sealing apparatus shown in FIGURE1;

FIGURE 3 is a simplified perspective view of the linkage utilized tomove the heating members of the carton sealing apparatus shown inFIGURES 1 and 2;

`FIGURE 4 is a fragmentary perspective View of one of the heatingmembers of the carton sealing apparatus shown in FIGURES l and 2;

FIGURE 5 is a perspective view of a cooling block ofthe carton sealingapparatus shown in FIGURES l and 2, with portions broken away to showthe internal construction thereof; vand FIGURE 6 is a perspective viewof a carton, such as might be sealed by the carton sealing apparatusshown in FIGURES l and 2, portions of the carton being broken away toshow the construction thereof.

The heat sealing apparatus in accordance with the present invention isadapted to seal cartons containing thermoplastic substances, such asmargarine, butter, etc., the cartons having heat sealing compound, suchas a thermoplastic lacquer, disposed between the overlapping -iiapsand/or walls thereof. The apparatus includes a frame which is providedwith means for defining a guideway for the cartons, the cartons beingpropelled along the guideway by a propelling means. Means are providedfor heating selected portions of the guideway defining means to renderthe thermoplastic compound tacky as the cartons are propelled along theguideway. Means are provided for cooling selected portions of theguideway dening means to set the compound as the cartons are propelledalong the guideway. Means are provided for rapidly reducing the heatapplied by the heating means to the guideway deiining means in case thepropelling means becomes inoperative.

While a carton sealing apparatus in accordance with the invention may beutilized to seal various sizes and shapes of cartons, the illustratedcarton sealing apparatus is particularly adapted for sealing a cartonsuch as that illustrated by the reference number 8 in FIGURE `6. whichcarton 8 is adapted to package 1/4 pound sticks of margarine.

The illustrated carton 8 includes a rectangular tube 10 formed by fourside walls 12, d4, 16 and 18, one of the side walls 18 being formed by apair of overlapping liaps 2@ and Z2. The tube l@ is provided with a topend wall 24 and a bottom end wall 26, each end wall Z4 and 26 beingformed by overlapping closure ilaps 28, 30, 32 and 34 integrallyconnected to the side walls 12, 14, 16 and 18, respectively.

Before the carton 8 is erected, the ap surfaces, which are -to underliethe outer aps are coated with heat sealing compound 36, such as heatsealing lacquer, which is non-tacking at room temperatures so that thecarton blanks do not stick to each other. For convenience, the heatsealing compound may be applied at the same time that the carton blanksare printed with descriptive information.

The carton sealing apparatus illustrated in the draw ings is adapted .tobe connected to the output or forward end of a packing machine 38 usedto package margarine. In general, the margarine packing machine 33 formsthe bulk margarine into 1A pound rectangular sticks, wraps the sticks ofmargarine with foil or suitable parchment paper, and feeds the sticksalong a horizontal path of travel.

As the sticks are moved along the packing machine 38, they are packedinto cartons 8, four sticks to each carton. The cartons 8, with theirside walls 14 forwardmost, are propelled along a. horizontally extendingguideway 40 at the output end of the packing machine 33 by a pushermechanism (not shown), the cartons 8 being pushed into a horizontallyextending guideway 41 at the left hand end, as shown in FIGURE 1, of thecarton sealing apparatus. For purposes of explanation, the left hand endof the carton sealing apparatus shown in FIG- URE 1 will be hereinafterreferred to as the rearward end, and the right hand end will be referredto as the forward end.

The carton sealing apparatus, as shown in the drawings, includes a frame42 which supports all of the operating elements of the carton sealingapparatus. The

' yceeding cartons 8. The gui and the -forwardly extending portions.

frame 42'is suitably fabricated from a pair of longi-Y 42 is supportedby a stand 47.

The Acartons 8. are pushed along the rearward guideway 41 of the cartonsealing apparatus by the succeeding cartons issuing from the outputguideway 4 0 of the packaging machine. In the illustrated embodiment,the lower surface of the rearward guideway 41 is provided by a pair oflo-ngitudinally extending, transversely spaced apart bottom rails 48which are disposed at such a height as to forni a continuation of thelower surface of the output guidewayV 40 of the packing machine 38.

The cartons 8 are guided as they are moved along the bottom rails 48,and the outer end wall flaps 28 are maintained in their closed position,by a pairl of spaced apart, longitudinally extending guide plates 50disposed so as to slidably engage the end walls I cartons 8. The outerflaps of therearward facing side walls 18 are maintained in Y de plates50 and the bottom rails 43 are `suitably mounted to the frameV 42 bybrackets 52 or such.

When the cartons 8 are propelled to the forward ends of the rails 48,they are successively rotated 90 by a chute or tumbler `54 so that theleading side wall 14 of each carton 8 faces downwardly. In theillustrated embodiment, the chute 54 includes a vertically extendingside wall S6 disposed ori each side of the path of travel of the cartons8, the wall 56 being suitably mounted to the frame 42.

The cartons 8 are guided downwardly in the chute 54 by a pivotallymounted upper guide 58 which includes a pair of transversely spacedapart strips 66 xedly mounted at their rearward ends to a transverselyextending shaft 62, which is journalled in apertures 64 1n the walls 56.The strips 60 are curved downwardly as shown iny FIGURE. l and thenceare" extended forwardly, the strips 60 being maintained in spaced apartrelation by al transversely extending rod 66 nxedly mounted below thestrips 60 at the intersection of the curved portions The rod 66 is madeof sufficient length to engage the upper edge of the side walls 56 ofthe chute 54 and thereby act as a stop Y for the downward travel of theguide 58. The guide '58 is urged downwardly by a tension spring 68connected between tlie end of the rod 66 and a projection (not shown) atthe side wall 56 of the chute 54.

v The carton S tumbles downwardly until the leading side wall 14 thereofstrikes a longitudinally extending horizontally disposed lower guideplate 70 which is suitably mounted tothe -frame 42.

A forward transversely extending pusher plate 72 .of areciprocating'mechanism 74, which is'operated in timed relationship withthe operation of the packaging machine 38, forms the rearward wall ofthe chute 54. The timing of the reciprocating mechanism 74 is such thatwhen the carton 8 strikes the lower guide plate 70, the reciproeatingmechanism 74 causes the pusher plate 72 to be moved forwardly, therebyengaging the rearward facing side wall 16 of the rotated carton 8.

The reciprocating mechanism 74 includes a pair of crank -arms 76 eachiixedly mounted by oneend to a shaft 78 journalled in bearings 80suitably mounted to the packaging machine 38, and by the other end to acommon pusher'rod 82. The'forward end of the pusher rod 82 is connectedto the pusher-plate 72 that is adapted to engage the rearward facingside wall 16 of the rotated carton 8. The Vreciprocating mechanism 74 isreciprocated by a crank armv 84 iixedly mountedV by one end to one ofthe shafts 78. The other end o-f the crank arm 84 is rotatably connectedto a tie rod 86 which 24and 26 of the v their closed positions by suc- Yis reciprocated by a timing mechanism, (not shown) in the packagingmachine 38. ,K

The reciprocating pusher mechanism 74 pushes the carton forwardly in thecarton sealing apparatus on its forward stroke, pivoting the upper guide58 upwardly. The rotated carton 8 is moved to. a position such that therod 66 drops therebehind. This prevents the rotated carton 8 fromfalling rearwardly when the pusher plate 72 is moved rearwardly. v

Succeeding cartons are prevented from falling behind the pusher plate 72when it is moved to its forward position by a horizontally disposedplate 88 fixedly mounted to the top of the pusher plate 72.

The rotated. cartons 8 Varegmoved forwardly along a guideway orpassageway 90 in the carton sealing apparatus by the rearwardmostrotated carton 8v being pushed forwardly by the pusher plate 72 ofreciprocating mechanism 74. In the illustrated embodiment, the guideway90 is defined by elongated upper and side sheets 92 and 94,respectively, of materialhaving ra smooth surface, a good heattransmission and good heat stability, such as plastic impregnated berglass, the-plastic being tetrailuoroethylene polymer, commerciallyavailable under the registered trademark Teflonf The sheets V92 and 94provide smooth surfaces for the passage ofthe cartons 8 while retainingthe outer ilaps 20 and 28 in a closed position.

In the illustrated embodiment, each-.vertically disposed side sheet 94is suitably anchored at its rearward end to the rearward edgerof avertically disposed block 96 which is suitably mounted to the frame 42.The forward end of each sheet `94 is disposed about the forward edge ofa side cooling member 98, which is described hereinafter, and isdrawntaut by a tensioning device 102 connected to the end of the sheet 94.

The tensioning device 102 includes a vertically disposed shaft 194journalled in bearings 106 suitably mounted to the frame 42, a crank arm108 connected to the lower end of the shaftV 104 anda spring 110corinected to the crank arm 108 for keeping the sheet 94 under tension.

The upper-sheet 92 is anchored at its rearward end to a transverselyextending bar 112 which is suitably mounted to the frame 42 and thevforward end of the upper sheet 92 is disposed about the forward edge ofan. upper cooling member 114, which Vis described hereinafter. The uppersheet 9.2 is maintained, in a tensioned condition by a tensioning device116 including a transversely extending shaft 1f18 attached to the end ofthe sheet 92 and journalled in bearings 120 suitably mounted to theframe 42. A crank arm l122 xedly mounted to one end of the shaft 118 anda spring y124` attached tothe crank arm 122 maintains the upper sheet 92under tension.

As each rotated carton -8 is pushed forwardly in the passageway 90, itpasses a plurality of heating members 126 and 128 located alongthe outersurfaceY of the Teflon sheetsy92 and 94, respectively. YThe members 126and 128 are heated sufficiently to render the heat sealing compoundtacky without melting themargarine within the cartons 8. In theillustrated embodiment, the heating members 126 and 28 are rectangularin shape and each includes three electrical heating elements 130. Eachheating member 126 and Y128 is provided with a pair of spaced' apartbearings 132 on its forward end by which the members 126 and 128 arelrotatably mounted on shafts 134y and 136, respectively, the shafts 134and 136 being suitably mounted to'the framev 42. Y

Applicants have found that, in order to properly seal the carton 8without melting the contents Within the carton, it is necessary tomaintain the temperature of the heating members '126 and V128 relativelyconstant, and also that it is preferable tov maintain, the forwardportion of the heating members 126 and 128 at a higher temperature thanthe rearward portion. Therefore, in the illustrated embodiment, therearwardmost heating element 130 in each member 126 and 128 iscontrolled by one adjustable thermostat 138, and the other two elements130 in the members 126 and 128 are connected in parallel and arecontrolled by a second adjustable thermostat 140. The thermostats 138and 140 are connected in parallel to a suitable source of power (notshown) by means of conductors 1142.

In order to prevent the contents within the cartons 8 from melting whenthe packaging machine is stopped for maintenance or for other purposes,a linkage means 144 is provided in the illustratedV embodiment to enablethe operator to move the heating members 126 and 128 away from theguideway 90, thereby reducing the heat applied to the cartons 8. Whenthe heating members 126 and 128 are moved away from the guideway 90, theouter flaps 20 and 28, which have a tendency to open, are retained intheir closed positions by the upper and side sheets 92 and 94. Thus, theheating members 126 and 128 may be moved back against the guideway 90,when the packaging machine becomes operative, without the necessity ofreclosing the aps 20 and 28.

As shown in the drawings, the linkage means 144 includes a tie rod 146rotatably connected by one end to the rearward portion of each sideheating member 128, the other end of each tie rod 146 being rotatblyconnected to one end of a common rocker arm 148. The rocker arm 148 isiixedly mounted intermediate its ends to a vertically disposed shaft150, the shaft 150 being journalled in bearings 152 suitably mounted tothe frame 42. 'Ihe shaft 150 is manually rotated by a lever 154 iixedlyattached to the lower end thereof whereby the side heating blocks 128are rotated about their associated shafts 136.

The upper heating member 126 is also moved by the rotation of the shaft150. The rotation of the shaft 150 is transmitted through a crank arm156 ixedly attached to the upper end thereof to a tie rod 158, one endof which is rotatably connected to the crank arm 156. The other end ofthe tie rod 158 is rotatably connected to the outer end of a secondcrank arm 160. The second crank arm 160 is xedly attached to ahorizontally disposed shaft y162 which is journalled in bearings 164suitably mounted to the frame 42.

The movement of the horizontally disposed shaft 162 is transmitted tothe upper heating member 126 by a third crank ann 166 xedly connected byone end to the shaft 162 and rotatably connected at its other end to atie rod 168 which tie rod 168 is rotatably connected to the rearwardportion of the upper heating member 126.

While the heating members 126 and 128 shown in the drawings are manuallymoved by the operator, it should be realized that the members 126 and128 may be moved automatically as by a solenoid.

After the heat sealing compound is rendered tacky by the heating members126 and 128, the cartons are moved along the guideway 90 to a coolingstation wherein the compound is set to thereby seal the cartons 8. Inthe illustrated embodiment, the cooling station includes upper and sidecooling members 114 and 98, respectively, disposed along the .top andsides of the guideway 90 adjacent the outer surface of the upper andside sheets 92 and 94, respectively. 'Ihe cooling members 114 and 98 arerectangular blocks suitably mounted to the frame 42 `and having coolingpassages 174 therein which are connected by exble hoses 176 to a source(not shown) of cooling water and a drain (not shown).

The cartons 8 after they pass through the cooling station, aresuccessively pushed onto a conveyor belt 178 which moves the cartons 8to succeding operations wherein the cartons 8 may be packed in shippingcontainers for shipment to the ultimate consumer. To insure that thecartons lie dat on the conveyor belt 178, the upwardly facing side walls18 of the cartons 8 are frictionally engaged by a flexible lip 180extending downwardly into the passageway the lip 180 being suitablymounted to a transversely extending bar 181 which, in turn, is mountedto the frame 42.

It is very important in the carton sealing apparatus to provide atemperature in the heating members 126 and 128 which is sufficient torender the heat sealing compound tacky but not enough to melt thecontents within the cartons 8. The heat transferred to a certain sizecarton depends mainly upon the speed of the carton S past the heatingmembers 126 and 128, the length of the heating members 126 and 128, thedistance between the heating members 126 and 128 and the cartons 8, andthe temperature at which the heating members 126 and 128 are maintained.In one embodiment of the invention, 11/2 inch thick cartons were movedpast the heating members at a rate of approximately 38 cartons perminute. The carton sealing apparatus was provided with eiective heatingmember lengths of approximately 5 inches, and .010 inch Teflon sheetsbetween the heating members and the cartons. At this rate of speed, atemperature of 320 F. proved to be an acceptable temperature for theheating members.

Various changes and modications may be made in the above describedcarton sealing apparatus without departing from the spirit or scope ofthe invention. Various features of the invention are set forth in theaccompanying claims.

We claim:

1. An apparatus for heat sealing cartons containing thermoplasticsubstances, the cartons having overlapping flaps on opposed sidesthereof and on a side thereof interconnecting the opposed sides andhaving heat sealing compound disposed between the overlapping flaps,said apparatus comprising a lframe, means on said frame including upper,side and bottom walls for dening a guideway for the cartons, means forpropelling the cartons along said guideway so that the interconnectingside is yadjacent the upper wall and the opposed sides are adjacent theside walls of said guideway defining means, said guideway being of sucha size that said walls are in sliding engagement with said cartons,means for applying heat to selected portions of the upper and side wallsof said guideway defining means, said heating means being at asufficient temperature to render the heat sealing cornpound tacky as thecartons are propelled along said guideway but not enough to melt thecontents within the cartons, means for cooling subsequent selectedportions of said guideway defining means to set the heat sealingcompound as the cartons are propelled along the guideway, and means onsaid frame for rapidly moving said heating means away from said guidewaydefining means to thereby rapidly reduce the heat applied by saidheating means to said guideway defining means.

2. An apparatus for sealing cartons containing thermoplastic substances,the cartons having heat sealing compound disposed between theoverlapping ilaps thereof, said apparatus comprising a frame, means onsaid frame defining a guideway for the cartons, means for propelling thecartons 'along said guideway, heating means disposed along selectedportions of the outer surfaces of said guideway deining means, saidheating means being movable between an operative position whereinsufficient heat is applied to the cartons as they are propelled alongsaid guideway to render the heat sealing compound tacky, and aninoperative position wherein the heat applied to the `cartons isinsuicient to melt the contents within the cartons, means on said framefor moving the heating means between said operative and said inoperativepos-itions, and means for cooling subsequent selected portions of saidguideway dening means to set the heat sealing compound as the cartonsare propelled along the guideway.

3.` An apparatus for sealing rectangular cartons containingthermoplastic substances issuing from a packing lmachine in ahorizontally extending path of travel, eachsaid frame defining aguideway for the cartons, means for propelling the rotated cartons alongsaid guideway, heating means pivotally mounted to the frame and disposedYalong selectedY portions of the outer surfaces of said guidewaydefining means, said heating means being movable between an operativeposition Ywherein suicient heat is applied to the cartons as they arepropelled along the guideway to render the heat sealing lacquer tackyand an inoperative position wherein .the heat applied to the cartons isinsuthcient to melt the contents within the cartons, means on said framefor moving said heating Cil 8. means between saidoperative position andsaid inoperative position, cooling means disposed along selectedportions of the outer surfacesof said guideway after the heating means,said cooling means being at a temperature such that the lacquer sets asthecartons are propelled along said guideway.

References` Cited in the tile of this patent UNITED STATESY PATENTS1,875,975 Alm Sept. 6, 1932 1,885,952 Schmitt Nov. 1, 1932 2,336,795Malhiot Dec. 14, 1943 2,420,763 Wells May'ZO, 1947 2,563,858 McGinleyAug. 14, 1951 2,727,345 Schoppee Dec. 20, 1955 2,855,977 Wagner Oct. 14,1958

